Device for shielding electrical terminals



DEVICE FOR SHIELDING ELECTRICAL TERMINALS Filed Oct. 1, 1959 INVENTOR.

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3,907,995 Patented Nov. 7, 1961 3,007,995 DEVItCE FOR SHIELDENG ELEQTRECAL TEPMENALS Joseph Schneiderman, 6649 N. Rockwell St.., Chicago, ill. Filed Oct. 1, 1959, Ser. No. 843,321 2 Claims. (Cl. 174--5) This invention relates to devices for shielding a pair of disconnectible electrical terminals which form the exposed ends of a pair of otherwise insulated, axially aligned conductors, while providing for frequent and ready access thereto for disconnection thereof.

Devices of this character find one important field of application in connection with neon and other signs wherein the sign proper must be detached from the secondary leads of the associated transformer at frequent intervals for cleaning, repair, access to surrounding surfaces, etc. To this end the terminals are bent into the form of a hook so that disconnection and connection may be rapidly effected. Local ordinances and requirements promulgated by insurance carriers invariably require that the exposed ends of the secondary at the points where they connect with the sign be protected against human contact at all times, even when the sign is detached for only a short period of time.

Therefore it has been the practice to utilize for this purpose a sleeve of glass which is of sufiicient length to be supported in operative position when resting on an adjacent part, or which may be taped into position. However, glass is easily broken and unprotected joints carrying high voltage remain an electrical hazard. Moreover where tape is required to maintain the operative position of the device a careless attendant may, following detachment of the tape and dislodgment of the sleeve for access, fail to re-tape the sleeve in position. Consequently electrical inspection bureaus and fire insurance underwriters have, more recently, made the use of safe devices practically mandatory. That is to say the device must be of non-frangible material, having high dielectric strength and include features insuring retention of the same in protective position.

Principal objects of my invention reside in providing an insulating sleeve for the indicated function which adequately serves to insulate electrically in accordance with approved practice, may not be easily broken and which is self-retaining in either of its two principal positions, viz., protecting the joint and exposing the joint.

Another object resides in accomplishing the foregoing objects by the use of a one-piece device of resilient but generally shape-retaining material.

Additional objects will become evident from the following description which, taken with the accompanying drawing, discloses a preferred mode of carrying the invention into practice.

In this drawing:

FIG. 1 is a side elevational view of the invention sleeve;

FIG. 2 shows a medial, longitudinal cross section thereof; and

FIG. 3 shows a top plan view.

Regarded broadly, the invention comprises a sleeve of electrically insulating material having some appreciable resiliency for manipulation in the intended manner but sufficiently rigid to maintain its shape. The interior of the sleeve is so proportioned as to receive the interengagcd terminals and to insure that the same are adequately protected against inadvertent human contact. At one end the sleeve is closed except for an opening sufficiently large for easy passage of one of the coupled conductors, e.g. one of the secondary leads of a neon sign transformer. Protruding into this opening is a tongue or ear having a degree of pliability such that the same will be deformed by the presence of the conductor and will therefore bear thereagainst with a force sufficient to retain the sleeve in any selected position on the conductor; that is to say, against the force of gravity if the conductor is vertically disposed. Thus, the sleeve may be moved along the conductor to expose the joint and, when the sleeve has been returned to shielding position, the sleeve will be reliably retained at such position.

Thus, turning to the drawing, I have shown a sleeve of suitably resilient material which is easily molded, possesses the resiliency required for proper function in the manner to be hereinafter described, is sufficiently shaperetaining and not frangible. Vulcanized rubber meets these objectives although polyethylene and similar resilient plastic compositions may be used.

The sleeve comprises a body portion 10 which may be a hollow cylinder of uniform diameter and wall thickness having an interior space suflicient to accommodate the hooked terminal ends 11 and 12 of a pair of interconnected conductors. By way of example, the conductor 11 is shown as one of the secondary leads of a transformer and the conductor 12 as one electrode of a neon sign 14.

One end of the sleeve is provided with a wall 16 having an aperture 17 of such size as to easily pass the insulation 18 of the conductor 11. Inasmuch as the diameter of the insulator 18 varies in practice the opening 17 will be made of such cross sectional area as to accommodate the largest of a selected group of conductors, e.g. for a range of inch diameter to inch diameter, in which case the diameter of the aperture 17 may A inch. The opening 17 may be represented as the interior of the body portion 10 in which case the end wall is unnecessary.

An ear 23 is provided at one side of the aperture 17 and projects into the latter sufficiently to bear against the insulation of the smallest diameter of conductor which the invention device is designed to accommodate, and as best shown in FIG. 2. Inasmuch as the ear 21 is unitary with the sleeve its resiliency will allow the necessary deformation thereof as the sleeve is shifted between its two principal positions, i.e. terminalshielding or terminal-exposing positions. Desirably the distal end of the car 21 may be rounded to enhance sliding on the insulation of the conductor and the wall 16 may be slit as at 22 to render the ear repeatedly deformable Without the hazard of fatigue failure.

The mode of operation will be apparent from FIG. 2. As the sleeve is shifted upwardly from the terminal-shielding position to the terminal-exposing position the ear 21 will flex oppositely from the position shown but will retain its frictional grip on the conductor 18 and, upon reverse movement, the ear will flex oppositely to resume the position shown.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made and I, therefore, contempiate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

I claim:

1. In combination with an interruptible junction of a pair of electrical conductors terminating in mutually en gageable hooks, the junction being adapted for occasional access but being otherwise shielded against the hazard of electrical shock, the conductors carrying electrical insulation beyond said hooks and the insulation being varied be tween upper and lower limits of diameter according to the voltage, a one-piece, elongated, hollow, cylindrical member of electrically-insulating, resilient, but generally shape-retaining material adapted to be shifted on one of the conductors between hook-shielding and hook-exposing positions, said member having an interior diameter accommodating said hooks, said diameter extending from one end of said member over the interior length thereof, said length being sufiicient to surround said hooks when the member is in hook-shielding position, the opposite end of said member having an end well, said wall having an opening therethrough for passage of said one conductor, the periphery of said opening being interrupted for a portion of its extent by a projection extending radially thereinto, said projection presenting a resiliently displaceable finger bearing on the insulation of said one conductor whereby said member may be shifted against the resulting bias of the finger from hook-shielding position to hook-exposing position and vice versa, the degree of friction being sufficient to overcome the force of gravity acting on said member when the same is installed in vertical position.

2. The combination in accordance with claim 1 further 4 characterized in that said end wall is pierced by a pair of slits, each extending substantially radially outwardly of said opening flanking said projection to increase the effective bending length of said projection.

References Cited in the file of this patent UNITED STATES PATENTS 1,689,690 Sandin Oct. 30, 1928 2,065,315 Keath Dec. 22, 1936 2,717,588 Arvanitakis Sept. 13, 1955 2,817,698 Schneiderman Dec. 24, 1957 2,948,937 Rapata Aug. 16, 1960 FOREIGN PATENTS 1,000,863 France Oct. 17, 1951 1,137,367 France Jan. 14, 1957 786,632 Great Britain Nov. 20, 1957 557,587 Canada May 20, 1958 

